Recently, the software manager hasn't been letting me install anything. I click the install button on whatever program I want, the button disappears, but nothing downloads. I've tried using the Ubuntu Software Center as well, and it tells me there's something wrong with my internet connection.

Also, when I run apt-get update, it tells me that there are a few unsigned repositories (or something along those lines.) This is obviously an issue of its own, but I wonder if the two are somehow connected?